System of pump control.



H. D. JAMES.

SYSTEM OF PUMP CONTROL.

APPLICATION FILED MAYH, 1914.

Patented July 3,1917.

WWW? ZWWQ INVENTOR H enry D. James. BY

ATTORNEY HENRY 1). JAMES, OFW-VVILKINSIBUBG, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELE CTRIC AND MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

SYSTEM OF PUMP CONTROL.

Specification of Letters Patent.

Patented July 3, 1917.

Application filed May 11, 1914. Serial No. 837,709.

To all whom it may concern:

Be it known that I, HENRY D. James, a citizen of the United States, and a resident of Wilkinsburg, in the county of'Allegheny and State of Pennsylvania, have invented a new and useful Improvement in Systems of Pump Control, of which the following is a specification.

My invention relates to systems of pump control and particularly to systems which embody centrifugal pumps.

My invention has for its object to provide a means for automatically controlling the output of centrifugal pumps or similar mechanisms.

It is well known that, pump be operated against a given head, a decrease in head increases the capacity of the pump at a ratiomuch greater than that of the corresponding decrease in head. If an electric motor be employed to drive a if a centrifugal pump, a reductionin head may causethe high, the motor will 80 motor to be seriously overloaded and, possibly, destroyed. The possibility of such an occurrence may be avoided by providing a motor of Suflicient capacity to operate the pump against the minimum head. If, however, the normal head be comparatively normally operate at less than its rated full-load capacity and,

' therefore, at a comparatively low efliciency.

I provide a system which comprises a means for automatically controlling the output of a centrifugal pump in accordance with the energy supplied to an electric motor which drives the pump. By this means, the energy delivered by the motor is limited, and an overload, which might result from a break in the delivery pipe, or other cause, is thereby prevented.

In the accompanying drawing, the single figure is a diagrammatic view of circuits and apparatus employed in connection wlth my invention.

Line conductors 1, 2 and 3, which may be connected to any suitable source of alternating current. supply energy to an induction motor 4 that is directly connected to a centrifugal pump 5. The pump 5 is provided with an intake pipe 6 and with a discharge pipe 7 which is controlled by a gate valve 8. An auxiliary electric motor 9, which controls the valve 8 by means of a worm gear mechanism 10, is also supplied operates, the volume with current from the line conductors 1, 2 and 3. The direction of rotation of the motor 9 is controlled by areversing switch 11 that is actuated by a bar 12 having a pivotal support indicated at 13. The bar 12 is controlled by an electromagnet comprising a coil 14 that is in series with the line conductor 3 and a movable core member 15.

It may be assumed that the pump. 5 is deliverlng water through the delivery pipe 7 against any given head and that the gate valve 8 is in its normal or open position. If the head against which the pump operates should be materially decreased from any cause, the capacity of the pump may be so increased as to overload the motor. lVhen the current supplied to the motor 4 through the line conductors reaches a predetermined value, the coil 14 will be sufficiently energized to actuate the core member 15 and the bar 12, and thus move the switch 11 to its upper position to close the circuit of the motor 9. The motor 9 then rotates in the proper direction to partially close the valve 8 and thus limit the quantity of water traversing the discharge pipe 7. The closing of the valve 8 operates, in effect, to maintain the head or back pressure, against which the pump operates, at a sub stantially constant value and thus compensate for the loss in head.

If the head be again increased, the capacity of the pump and, consequently, the load upon the motor 4 will be correspondingly decreased. When the current traversing the coil 14 falls to a predetermined value, the switch 11 assumes its lower position to complete the circuit of the motor 9. Since the switch 11 reverses the connections of two of the phases of the motor winding, the motor 9 will rotate in the reverse direction to open the valve 8 and thus allow an increased quantity of water to flow through the pipe 7. The opening of the valve 8 operates to remove the artificial head created by its closing.

It will be noted that I provide a system in which the head against which the pump of water delivered and by the driving motor are maintained at a substantially constant value. The controlling means employed in the system constitute a safety device which operates in case of emergency to prevent the power received the destruction of, or the damage to, a motor, the capacity of which is below that necessary to operate the pump against a minimum head. My invention may be employed with especial advantage in connection with irrigation systems in which motor-driven pumps are operated practically continuously with only occasional inspection by the attendant.

While I have shown and described my invention as applied to a centrifugal pump, it is applicable, also, to fans, blowers or other fluid-impelling devices having similar inherent characteristics.

I claim as my invention:

1. In a system of pump control, the combination with a pump, a pipe connected thereto, and means-for driving said pump, of means for automatically controlling the flow of fluid in said pipe. in accordance with the energy delivered to said driving means.

2. In a system of pump control, the com.-'

bination with a pump, a pipe connected thereto, a valve in said'pipe, and a motor for driving said-pump, of means for controlling said valve in accordance with the energy delivered to said motor.

3. In a'system of pump control, the combination with a pump having a delivery pipe, a valve in said pipe, and an electric motor for driving said pump, of means controlled by the current supplied to said motor for controlling said valve.

4. In a system of pump control, the combination with a pump, a delivery pipe therefor, a valve in said pipe, and an electric motor operatively connected to said pump, of an auxiliary electric motor for controlling said valve, a reversing switch for said motor and means comprising a coil in series copies of this patent may be obtained for five cents each, by Washington, D. 8.

with the main motor for controlling said switch.

5. In a system ofpump control, the combination with a fluid pump, and driving means therefor, of electro-responsive means for maintaining the volume of fluid delivered by said pump at a substantially constant value, said means comprising a valve and means for controlling said valve in accordance with the amount of energy supplied to said driving means.

6. In a system of pump control, the combination with a pump, and driving means tric motor for driving said device, of means for controlling the flow of fluid actuated by said device in accordance with the energy supplied to said motor.

In testimony whereof, I have hereunto subscribed my name this 30th day of April,

HENRY D. JAMES.

Witnesses:

GEo. F. Nnncmne, B. B. HINES.

addressing the Commissioner of Patents, 

